This application relates to a method and apparatus for the detection of optic neuropathy, particularly detection of glaucoma, brain tumors affecting the optic nervous system and other optic nerve diseases. The method and apparatus exploit the differential ability of normal and optic neuropathy patients to detect paracentrally presented sinusoidal grating patterns truncated at different diameters by a Gaussian aperture.
Sinusoidal grating patterns have been used as part of various test methods for testing foveal vision. The grating pattern appears as a series of bars, the spacing of which depends on the frequency of the sine wave employed to generate the pattern. A generally circular outline is established by truncating the pattern with a Gaussian aperture.
Foveal vision tests are in many cases inadequate for detecting the early signs of glaucoma, brain tumors and other optic nerve diseases. For example, in the early stages of glaucoma, the damage to the optic nerve is diffuse, or may occur in only certain types of neurons rather than being concentrated in individual bundles of the optic nerve. Because of this, discrete field defects may not be detected.
To provide for early detection of the optic nerve damage, therefore, it would be highly desirable to have a mechanism which was capable of detecting diffuse damage to the optic nerve. It is an object of the present invention to fulfill this need.